Cutter head for suction dredge

ABSTRACT

A truncated, conical cutting head for a suction dredge constructed of simplified wearing parts and strength members which may be easily assembled and removed for replacement. The cutter head has blades directly attached to strengthening struts with the blades inclined in the direction of rotation of the head. Cutter teeth which extend radially outwardly beyond the blades are also attached directly to the struts. Both the struts and the blades are formed of straight pieces of material of conventional cross-sections such as rectangular or square, which have been cut to fit. Lifter plates are provided in the cutter head between the hub and the blades to move material to the inlet of the suction mouth.

United States Patent [1 1 [1 1 3,807,066

Proehl Apr. 30, 1974 CUTTER HEAD FOR SUCTION DREDGE 57] ABSTRACT [76] Inventor; Norman Proehl, 373 Westminster A truncated, conical cutting head for a suction dredge Ave-i Lake Forest 60015 constructed of simplified wearing parts and strength [22] Filed; 29, 7 members which may be easily assembled and removed for replacement. The cutter head has blades directly 1 DM- 3 attached to strengthening struts with the blades inclined in the direction of rotation of the head. Cutter 52 us. Cl. 37/67, 37/189 teeth which extend radially outwardly beyond the [51] Int. Cl E02f 3/92 blades are also attached directly to the Struts- Both the [58] Field of Search 37/67, 189 Struts and the blades are formed of Straight pieces of material of conventional cross-sections such as rectan- [56] References Cited gular or square, which have been cut to fit. Lifter plates are provided in the cutter head between the hub 2 999 324 ZL' Z PATENTS 37/67 and the blades to move material to the inlet of the sucausen .L 1,436,015 11/1922 Cushing 37/67 non f 2,370,430 2/1945 Waldeck.... 37/67 709,861 9/1902 Bates 37/67 Primary ExaminerRobert E. Pulfrey 4 C 4 Drawing Figures Assistant Examiner-Clifford D. Crowder A Attorney, Agent, or FirmKinzer, Plyer, Dom 8:

McEachran CUTTER HEAD FOR SUCTION DREDGE SUMMARY OF THE INVENTION This invention is directed to a cutter head for a suction dredge and more particularly to a cutter head that is efficient to operate, economical to build and repair and easy to modify for digging different types of material.

An object of this invention is a cutter head which can be manufactured from readily available materials that do not have to be specially cast, forged or machined.

Another object is a cutter head having both structural and wearing parts which may easily be replaced.

Another object is a cutter head having inclined material moving blades whose angle of inclination may be varied depending on the type of material being dug.

Another object is a cutter head having cutting teeth, the number and location of which may be easily varied.

Another object is a cutter head which will not pick up rocks large enough to block the inlet of the suction pipe.

Another object is a cutter head having lifter means for feeding the materials being dug to the inlet of the suction pipe.

Another object is a cutter head that reducesturbulence and false vacuum during digging operations.

Another object is a cutter-head that reduces turbulence and false vacuum during digging operations.

Another object is a cutter that leaves a clean bottom thereby reducing the amount of overdigging required to dig to a fixed fiat grade.

Other objects may be found in the following specification, claims and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS The invention isillustrated more or less diagrammatically in the following drawings wherein:

FIG. 1 is a rear elevational view of the cutter head of this invention with parts broken away for clarity of illustration;

FlG.'2 is a longitudinal, cross-sectional view of the cutter head of FIG. 1;

FIG. 3 is a cross-sectional view taken along line 33 of FIG. 2; and

FIG. 4 is a top plan view of the elementsof FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENT A cutter head 11 embodying the novel features of this invention includes a front end plate assembly 13 having an outer end plate 15 in the shape of a truncated cone and an inner end plate 17 of the same shape joined together. Although the front end plate assembly is shown in this embodiment consisting of two pieces, it should be understood that it is also possible to manufacture it in a single piece. However, the use of two pieces permits adjustment of the length of the cutter head by either the elimination of the inner plate 17 or a change in thickness of this plate.

A cylindrical hub 19 having a socket 21 which receives the drive shaft (not shown) for the cutter head is mounted on the inner surface of the front end plate assembly 13. A base ring 23 of greater diameter than the front end plate assembly 13 is connected to the front end plate assembly by struts 25 of generally rectangular cross-section. The struts are connected to the front end plate assembly and to the base ring by welding with the ends of the struts cut at the proper angles to permit connection of the struts to the surfaces of said members.

Blades 27, which are straight members of generally rectangular cross-section, are attached to the struts 25, to the front end plate assembly 13 and to the base ring 23 by welding. The blades are tilted in the direction of rotation of the head. The angle of inclination of the blades may be varied depending on the material being dug. In the embodiment shown, the blades are positioned at an angle of 30 relative to the tangent. Also, the manner of attachment of the blades to the struts may be varied although welding is the prefered manner.

Cutting teeth 29 are mounted on the struts 25 so as to extend radially of the cutter head and to project outwardly beyond the outer edge of the blades 27. The cutting teeth preferably are formed of a good wearing quality steel and may be of a sheath type so that they can be quickly changed. A number of teeth per strut and the spacing between the teeth on a strut may be varied depending upon operating conditions. The size and the hape of the cutting teeth may also be varied depending upon the type of material to be dug, the speed of rotation on the cutter head, etc.

Lifting members 39 are mounted on the rear surface of the front end plate assembly 13 between'the hub 19 and the blades 27. The lifting members include plates 41 which are inclined so as to move the material being cut away from the front end plate assembly 13 and towards thebase ring 23.'Each inclined plate is formed integrally with a base member 43 which is bolted to'the front end plate assembly 13. Of course, other methods of connecting the lifter members to the front end plate assembly may also be utilized. Further, instead of an integral inclined plate and base member, the lifting members may be made of separate pieces connected together in a suitable manner.

The inclination of the plate 41 relative to the base member 43 may be varied depending upon the material to be dug. Also, the shape of the inclined plate may also be varied. While two lifting members are shown in this embodiment of the invention, it should be understood that additional lifting members may also be provided. Generally thelifting members are positioned diametrically of each other to provide balance. However, other arrangements of lifting members may also be found to be feasible.

The cutter head-11 mounts on a circular support plate 47 which fits inside the base ring 23. The circular support plate mounts on a suction dredge ladder but this is not shown since it is conventional. A kidney shaped suction pipe opening 49 is provided in the support plate and leads to a suction pipe 51 which also mounts on the suction dredge ladder.

The use, operation and function of this invention are as follows:

Hydraulic dredging is a highly competitive business in which extremely large amounts of material must be removed rapidly and at minimum cost in order for a contractor to be successful. The cutter heads presently used commercially are expensive to manufacture and repair. Additionally, the commercially available cutter heads do not cut or dig efficiently on the walking swing of the cutting ladder. This is because most commercially available cutting heads have blades which are curved to a spiral or helical connection at the front end of the cutter head. The spiral front end of the cutter head is practically flat and prevents the head from digging in to the material beint cut when the head is moved in the walking swing of the cutter ladder.

The cutter head of this invention is designed so that it can be manufactured from straight, generally stock pieces of metal without the need for elaborate bending, forging, casting or machining steps to provide the cutting surfaces. To this end, the struts and blades are formed of straight pieces of metal of generally rectangular cross-section which can be easily cut to connect between the front end plate assembly 13 and the base ring 23. The blades are inclined in the direction of rotation of the cutter head and in this example are positioned at an angle of about 30 to the tangent. However, this angle can be adjusted depending on the material being dug and the desired speed of rotation of the cutter head. The inclination of the blades also limits their radial projection and thereby reduces turbulence and lowers the amount of false vacuum created by the blades during rotation of the cutter head. Turbulence and false vacuum are also reduced by the positioning of the struts 25 with their minimum cross-sectional dimensions extending radially of the cutter head. Because of the straight shape of the blades 27 and their rectangular cross-sections, it is relatively easy to change the angle of inclination of the blades. Also, as the blades 27 wear out, they can easily be replaced. Further, replacement will necessarily be infrequent since the leading edges of these blades will be sharpened by engagement with the material being dug.

The digging teeth 29 extend beyond the blades 27 to provide the initial scarifyin g, harrowing, ripping, raking or digging of the materials to be cut. The teeth will dig or loosen the material in advance of the blades. This reduces wear on the blades and also permits the cutter head to operate efficiently under conditions where tree roots and stumps are present as well as in cold climates where there is permafrost. The spacing of the digging teeth in connection with the spacing of the blades will determine the dimensions of rocks or other foreign objects which will pass through the cutter head. The spacing of the blades 27 around the periphery of the cutter head in conjunction with the speed of rotation of the cutter head will determine the transverse travel of the adjacent blades as the dredge ladder moves through its digging are. This distance will determine one dimension of a rock or foreign object which may enter the cutter head. The teeth 29 may then be spaced a similar longitudinal distance along the struts to provide the same limiting dimension on any foreign object.

Whereas, five sets of struts and blades have been shown on the cutter head of this embodiment with three digging teeth mounted on each strut, it should be understood that greater or lesser numbers of struts and teeth may be used depending on the size of the cutter head. Also, of course, the number of teeth may also be varied.

The lifting members 39 move the material that enters the cutter head towards the suction outlet 49 at the rear of the cutter head. The inclined plates may be varied both in angle of inclination and in size depending on the material to be moved and the speed of rotation of the cutter head. Also, the number of lifting members may also be varied. The lifting members enable the cutter head to do a more efficient job of removing material to the full depth of the cutter head. Thus, with a cutter head having lifting members it will be possible to obtain a clean bottom without excessive digging below the desired grade.

Whereas, the preferred form of the invention has been described and shown, it should be understood that there are modifications, alterations and changes which may be made without departing from the teachings of the invention. Therefore, the scope of the invention should be only limited by the claims attached hereto.

I claim:

1. A cutter head for a suction dredge, including:

a hub,

a circular plate mounted on the forward end of said hub,

a back ring of greater diameter than said circular plate,

struts extending between said circular plate and said back ring and connected near the periphery thereof to form a truncated, conical structure,

blades connected to said struts and inclined in the direction of rotation of said cutter head, and

a plurality of inclined lifter plates attached to said circular plate on the hub side thereof and inside of said blades.

2. A cutter head of claim 1 further characterized in that said lifter plates are inclined to lift material rearwardly from said hub when said cutter head is rotated in the direction of inclination of said blades.

3. The cutter head of claim 1 further characterized in that said lifter plates are installed in pairs located generally diametrically of each other.

4. The cutter head of claim 1 further characterized in that said cutting teeth are attached to said struts and are positioned along the length thereof with said teeth extending radially and projecting outwardly beyond the end of said blades.- 

1. A cutter head for a suction dredge, including: a hub, a circular plate mounted on the forward end of said hub, a back ring of greater diameter than said circular plate, struts extending between said circular plate and said back ring and connected near the periphery thereoF to form a truncated, conical structure, blades connected to said struts and inclined in the direction of rotation of said cutter head, and a plurality of inclined lifter plates attached to said circular plate on the hub side thereof and inside of said blades.
 2. A cutter head of claim 1 further characterized in that said lifter plates are inclined to lift material rearwardly from said hub when said cutter head is rotated in the direction of inclination of said blades.
 3. The cutter head of claim 1 further characterized in that said lifter plates are installed in pairs located generally diametrically of each other.
 4. The cutter head of claim 1 further characterized in that said cutting teeth are attached to said struts and are positioned along the length thereof with said teeth extending radially and projecting outwardly beyond the end of said blades. 